There are many situations in which relatively heavy objects must be lifted and/or suspended (and/or lowered under control). For example, hunters must often suspend heavy animals (e.g., from a tree) for cleaning purposes; furniture and other heavy objects must be loaded onto trucks; trunks/crates must be moved to attics or garage lofts; portions of smaller vehicles (e.g., ATVs) must be lifted for purposes of changing a tire or pulled out of a stuck situation; and so on. In many instances, even a strong individual is unable to lift the objects in the desired manner.
The same can hold true when someone wants to introduce an optimum amount of tension in a line of some sort. For example, during the construction of a barbed-wire fence, the wire must be pulled tight to create a viable fence. Pulling the wire tight can be difficult or impossible for even a strong individual.
One mechanism that can aid in lifting such objects and/or pulling such objects tightly is a block-and-tackle configuration. Block-and-tackles involve arranging one or more pulleys in relation to a fixed object and feeding rope through the pulleys in such a way as to create a mechanical advantage. In this way, by pulling the rope over a longer distance, a greater lifting force can be achieved.
In many instances, configuring a block-and-tackle can present difficulties. Feeding the rope through the pulley(s) and/or attaching the load to the block-and-tackle can pose challenges that limit the usefulness and/or applicability of block-and-tackles.